"gprof" produces an execution profile of C, Pascal, or Fortran77
programs. The effect of called routines is incorporated in the profile of each
caller. The profile data is taken from the call graph profile file (
gmon.out default) which is created by programs that are compiled with
the -pg option of "cc", "pc", and "f77".
The -pg option also links in versions of the library routines that are
compiled for profiling. "Gprof" reads the given object file (the
default is "a.out") and establishes the relation between its symbol
table and the call graph profile from gmon.out. If more than one
profile file is specified, the "gprof" output shows the sum of the
profile information in the given profile files.

"Gprof" calculates the amount of time spent in each routine. Next,
these times are propagated along the edges of the call graph. Cycles are
discovered, and calls into a cycle are made to share the time of the cycle.

Several forms of output are available from the analysis.

The flat profile shows how much time your program spent in each function,
and how many times that function was called. If you simply want to know which
functions burn most of the cycles, it is stated concisely here.

The call graph shows, for each function, which functions called it, which
other functions it called, and how many times. There is also an estimate of
how much time was spent in the subroutines of each function. This can suggest
places where you might try to eliminate function calls that use a lot of time.

The annotated source listing is a copy of the program's source code,
labeled with the number of times each line of the program was executed.

These options specify which of several output formats "gprof" should
produce.

Many of these options take an optional symspec to specify functions to be
included or excluded. These options can be specified multiple times, with
different symspecs, to include or exclude sets of symbols.

Specifying any of these options overrides the default ( -p -q), which
prints a flat profile and call graph analysis for all functions.

"-A[symspec]"

"--annotated-source[=symspec]"

The -A option causes "gprof" to print
annotated source code. If symspec is specified, print output only
for matching symbols.

"-b"

"--brief"

If the -b option is given, "gprof" doesn't
print the verbose blurbs that try to explain the meaning of all of the
fields in the tables. This is useful if you intend to print out the
output, or are tired of seeing the blurbs.

"-C[symspec]"

"--exec-counts[=symspec]"

The -C option causes "gprof" to print a
tally of functions and the number of times each was called. If
symspec is specified, print tally only for matching symbols.

If the profile data file contains basic-block count records, specifying the
-l option, along with -C, will cause basic-block execution
counts to be tallied and displayed.

"-i"

"--file-info"

The -i option causes "gprof" to display
summary information about the profile data file(s) and then exit. The
number of histogram, call graph, and basic-block count records is
displayed.

"-I dirs"

"--directory-path=dirs"

The -I option specifies a list of search directories
in which to find source files. Environment variable GPROF_PATH can
also be used to convey this information. Used mostly for annotated source
output.

Normally, source filenames are printed with the path
component suppressed. The -L option causes "gprof" to
print the full pathname of source filenames, which is determined from
symbolic debugging information in the image file and is relative to the
directory in which the compiler was invoked.

"-p[symspec]"

"--flat-profile[=symspec]"

The -p option causes "gprof" to print a
flat profile. If symspec is specified, print flat profile only for
matching symbols.

The -t option causes the num most active
source lines in each source file to be listed when source annotation is
enabled. The default is 10.

"-y"

"--separate-files"

This option affects annotated source output only. Normally,
"gprof" prints annotated source files to standard-output. If
this option is specified, annotated source for a file named
path/filename is generated in the file
filename-ann. If the underlying file system would
truncate filename-ann so that it overwrites the
original filename, "gprof" generates
annotated source in the file filename.ann instead (if
the original file name has an extension, that extension is replaced
with .ann).

"-Z[symspec]"

"--no-exec-counts[=symspec]"

The -Z option causes "gprof" not to print
a tally of functions and the number of times each was called. If
symspec is specified, print tally, but exclude matching
symbols.

"-r"

"--function-ordering"

The --function-ordering option causes
"gprof" to print a suggested function ordering for the program
based on profiling data. This option suggests an ordering which may
improve paging, tlb and cache behavior for the program on systems which
support arbitrary ordering of functions in an executable.

The exact details of how to force the linker to place functions in a
particular order is system dependent and out of the scope of this
manual.

"-R map_file"

"--file-ordering map_file"

The --file-ordering option causes "gprof"
to print a suggested .o link line ordering for the program based on
profiling data. This option suggests an ordering which may improve paging,
tlb and cache behavior for the program on systems which do not support
arbitrary ordering of functions in an executable.

Use of the -a argument is highly recommended with this option.

The map_file argument is a pathname to a file which provides function
name to object file mappings. The format of the file is similar to the
output of the program "nm".

The -T option causes "gprof" to print its
output in "traditional" BSD style.

"-w width"

"--width=width"

Sets width of output lines to width. Currently only
used when printing the function index at the bottom of the call
graph.

"-x"

"--all-lines"

This option affects annotated source output only. By
default, only the lines at the beginning of a basic-block are annotated.
If this option is specified, every line in a basic-block is annotated by
repeating the annotation for the first line. This behavior is similar to
"tcov"'s -a.

"--demangle[=style]"

"--no-demangle"

These options control whether C++ symbol names should be
demangled when printing output. The default is to demangle symbols. The
"--no-demangle" option may be used to turn off demangling.
Different compilers have different mangling styles. The optional
demangling style argument can be used to choose an appropriate demangling
style for your compiler.

The -a option causes "gprof" to suppress
the printing of statically declared (private) functions. (These are
functions whose names are not listed as global, and which are not visible
outside the file/function/block where they were defined.) Time spent in
these functions, calls to/from them, etc., will all be attributed to the
function that was loaded directly before it in the executable file. This
option affects both the flat profile and the call graph.

"-c"

"--static-call-graph"

The -c option causes the call graph of the program
to be augmented by a heuristic which examines the text space of the object
file and identifies function calls in the binary machine code. Since
normal call graph records are only generated when functions are entered,
this option identifies children that could have been called, but never
were. Calls to functions that were not compiled with profiling enabled are
also identified, but only if symbol table entries are present for them.
Calls to dynamic library routines are typically not found by this
option. Parents or children identified via this heuristic are indicated in
the call graph with call counts of 0.

"-D"

"--ignore-non-functions"

The -D option causes "gprof" to ignore
symbols which are not known to be functions. This option will give more
accurate profile data on systems where it is supported (Solaris and HPUX
for example).

"-k from/to"

The -k option allows you to delete from the call
graph any arcs from symbols matching symspec from to those matching
symspec to.

"-l"

"--line"

The -l option enables line-by-line profiling, which
causes histogram hits to be charged to individual source code lines,
instead of functions. This feature only works with programs compiled by
older versions of the "gcc" compiler. Newer versions of
"gcc" are designed to work with the "gcov" tool
instead.

If the program was compiled with basic-block counting enabled, this option
will also identify how many times each line of code was executed. While
line-by-line profiling can help isolate where in a large function a
program is spending its time, it also significantly increases the running
time of "gprof", and magnifies statistical inaccuracies.

"--inline-file-names"

This option causes "gprof" to print the source
file after each symbol in both the flat profile and the call graph. The
full path to the file is printed if used with the -L option.

"-m num"

"--min-count=num"

This option affects execution count output only. Symbols
that are executed less than num times are suppressed.

"-nsymspec"

"--time=symspec"

The -n option causes "gprof", in its call
graph analysis, to only propagate times for symbols matching
symspec.

"-Nsymspec"

"--no-time=symspec"

The -n option causes "gprof", in its call
graph analysis, not to propagate times for symbols matching
symspec.

"-Sfilename"

"--external-symbol-table=filename"

The -S option causes "gprof" to read an
external symbol table file, such as /proc/kallsyms, rather than
read the symbol table from the given object file (the default is
"a.out"). This is useful for profiling kernel modules.

"-z"

"--display-unused-functions"

If you give the -z option, "gprof" will
mention all functions in the flat profile, even those that were never
called, and that had no time spent in them. This is useful in conjunction
with the -c option for discovering which routines were never
called.

The -s option causes "gprof" to summarize
the information in the profile data files it read in, and write out a
profile data file called gmon.sum, which contains all the
information from the profile data files that "gprof" read in.
The file gmon.sum may be one of the specified input files; the
effect of this is to merge the data in the other input files into
gmon.sum.

Eventually you can run "gprof" again without -s to analyze
the cumulative data in the file gmon.sum.

"-v"

"--version"

The -v flag causes "gprof" to print the
current version number, and then exit.

These options have been replaced with newer versions that use symspecs.

"-e function_name"

The -efunction option tells
"gprof" to not print information about the function
function_name (and its children...) in the call graph. The function
will still be listed as a child of any functions that call it, but its
index number will be shown as [not printed]. More than one
-e option may be given; only one function_name may be
indicated with each -e option.

"-E function_name"

The "-E function" option works like the
"-e" option, but time spent in the function (and children who
were not called from anywhere else), will not be used to compute the
percentages-of-time for the call graph. More than one -E option may
be given; only one function_name may be indicated with each
-E option.

"-f function_name"

The -ffunction option causes
"gprof" to limit the call graph to the function
function_name and its children (and their children...). More than
one -f option may be given; only one function_name may be
indicated with each -f option.

"-F function_name"

The -Ffunction option works like the
"-f" option, but only time spent in the function and its
children (and their children...) will be used to determine total-time and
percentages-of-time for the call graph. More than one -F option may
be given; only one function_name may be indicated with each
-F option. The -F option overrides the -E
option.

The granularity of the sampling is shown, but remains statistical at best. We
assume that the time for each execution of a function can be expressed by the
total time for the function divided by the number of times the function is
called. Thus the time propagated along the call graph arcs to the function's
parents is directly proportional to the number of times that arc is traversed.

Parents that are not themselves profiled will have the time of their profiled
children propagated to them, but they will appear to be spontaneously invoked
in the call graph listing, and will not have their time propagated further.
Similarly, signal catchers, even though profiled, will appear to be
spontaneous (although for more obscure reasons). Any profiled children of
signal catchers should have their times propagated properly, unless the signal
catcher was invoked during the execution of the profiling routine, in which
case all is lost.

The profiled program must call "exit"(2) or return normally for the
profiling information to be saved in the gmon.out file.

Permission is granted to copy, distribute and/or modify this document under the
terms of the GNU Free Documentation License, Version 1.3 or any later version
published by the Free Software Foundation; with no Invariant Sections, with no
Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is
included in the section entitled "GNU Free Documentation
License".